ABSTRACT:Oral controlled release matrix tablets of zidovudine were prepared by wet granulation technique using ethyl cellulose. The effect of the concentration of the polymer was studied. The studies indicated that the drug release can be modulated by varying the concentration of the polymer. The prepared tablets were evaluated for various physiochemical parameters by official procedures. The in vitro release study of matrix tablets were carried out in phosphate buffer pH 6.8 for 12 hours. The prepared matrix tablets were shown 98.42%, 96.52%, 88.90%, 82.21%, and 73.76% release over a period of 12 hours. Among all the formulation, F2 shows 96.52% release at the end of 12 hours. Selected formulation (F2) was subjected to stability studies for three months, which showed stability with respect to release pattern. The release data was fitted to various mathematical models such as, Higuchi, Korsmeyer-Peppas, First-order, and Zero-order to evaluate the kinetics and mechanism of the drug release. The release profile of the developed formulations was described by the Higuchi model and the mechanism was found to be an anomalous (non-fickian) diffusion transport mechanism.